TV ocassionally looses power and turns off, othertimes will work fine.

Hi,

I have a CRT (old style) television in my kitchen its a few years old which has started to turn itself off. Sometimes it will work without a problem then suddenly turn itself off, it seems like the power has drained from it, the LED power light fades. Turning it off and on again sometimes solves the problem however often the TV turns on again and loses power almost immediately.

From a very limited knowledge of electronics I was wondering if there could be problems with a capacitor. Or is it likely to be due to the power supplied to the tv, I have tried it on different plugs and the problem seems to remain.

It might be something to do with the actual electricity of the house. We had some faulty wires that were that would make the lights turn off after a while, or other little things like that. We thought that out appliances were all breaking at once, but we got some wires replaced and it works now. http://ctenergysavings.com/epp/suppliers

4 Answers

Capacitors hold a charge of electricity over time, and are used in the power supply of the TV. Some types can fail over time due to humidity, or heat.

Working on a CRT can be very dangerous due to the high voltages that can be stored inside even after the power is removed.

I would try to find a local electronics repaid shop, most of them made their start working on CRT TVs and they would have the expertise to repair them.

If you do want to do it yourself you have to first leave the TV unplugged for a few hours. Then take it apart, being careful not to touch any of the circuits. Then look for any blown or damaged capacitors, they would look bloated on the top of the can. Write down the specifications of each of these capacitors, find the equivalent replacements from an electronics store, and remove and re-solder them. But NONE of the above is easy, power suppliers need powerful soldering irons, and there is no guarantee the failure is the capacitors alone.

Another possibility is a failing circuit breaker. Check the back of the TV and see if you can find something labeled RESET. If so the next time it fails press the reset and see what happens. Not all units have circuit breakers but if yours does it could be starting to fail from age. If it is a CB its a much easier repair. Ralph

A possible problem, which may cause symptoms as described, is that dust etc. has accumulated on the components and is causing heat buildup. Blowing it out with compressed air, maybe without removing the case, may solve problem.

James, it could be capacitors, transistors, resistors, or pretty much anything. It does not appear to be a heating problem, or anything related to time. It is most likely a loose connection, like a cold solder joint (good at first, but fails over time). The good thing is that it appears to be in the power supply section.

If it is an old TV, but just old enough to have a multi-function circuit board, this may not be good, but only a technician should be looking. What is the value of the TV? The repair may be more expensive than finding a good used TV at a repair shop (or Goodwill).

If it is a very old TV, it may have modular electronics, such that just the power supply could be changed, which you could do yourself. Again, what value do you place on the TV? And, the modular component may be difficult to find.

The place where the dangerous voltages exist are in the video circuits, and particularly in the flyback transformer circuits. Look for a large lead going to the CRT (picture tube), note where it goes, and stay away from both ends, even months after removing power.